Overview: Ann Hamilton, who works with textiles; impish multimedia artist John Feodorov; miniaturist Shahzia Sikander; and James Turrell, whose medium is light itself. Linking them: spirituality, "a thread that connects us all," says host S. Epatha Merkerson. "I think ambiguity is where the spiritual lies," says Feodorov, who combines Navajo and Christian themes provocatively. Turrell explains how he designs his projects "to bring the cosmos closer."